Ultrasonic insect repellent circuit

The electrical pulse generated by the time base circuit is output by pin ③, and then sent to the piezoelectric speaker BLD through R6, which switches the electrical pulse into ultrasonic waves and
radiates into the space. The frequency sweeping principle of this circuit is also very simple. The secondary low-voltage AC signal of the transformer is used to modulate the ⑤ pin of the 555 time base circuit
to achieve the purpose of changing the pulse frequency. The frequency range is 32kHz ~ 62kHz.
    According to relevant foreign information, this device is multi-purpose and can repel rats, cockroaches, and fleas, and its effective area can reach 1 6rr12. As long as the device
is placed indoors, connected to the power supply, and works continuously, the rats, cockroaches, and fleas will decrease over time. The purpose of getting rid of the above-mentioned pests can be achieved within three months
, and there will be no rats, cockroaches, or fleas in the room. Cockroaches and fleas. If the housing area is large, you can put a few more indoors.